Generally, Colon is used to call the reader’s attention to what comes next.
1. Use a colon before a list of items, especially after expression like as follows and the following.
* At the crossroads we saw three signs: To Lagos, To Ondo, and To Bayelsa.
If a list follows immediately after a verb or a preposition, do not use a colon:
INCORRECT: You used to shop for: brown bag, a pack of milk, and four spoons.
CORRECT: You need to shop for brown bag, a pack of milk, and four spoons.
2. Use a colon before a long, formal statement or quotation.
Example: Nnamdi had this to say about dealing with with those who disagreed with you: “Do not think of knocking out another person’s brains because he differs in opinion from you. It would be as rational to knock yourself on the head because you differ from yourself six years ago”.
3. A colon is used in certain conventional situations.
* Between the hour and the minute when you write the time. 9:30 a.m.
* A colon is used between chapter and verse in referring to passages from the Bible. Esther 3:5